Oxygen regulator



Aug. 3l, 1943. B. B. HOLMES OXYGEN REGULATOR Filed Dec, 26, 1940 4 Sheets-Sheet 1 JMW@ l Aug. 31, 1943. B. B. HOLMES 2,328,214'

OXYGEN REGULATOR' FiledDec. 26, 1940 4 Sheets-Sheet 2 @8&3

Bradford, B

Aug. 31, 1943. 8,' B, HQLMES n 2,328,214

OXYGEN REGULATOR Filed Dec. 2e, 1940 4 sheets-sheet s gwoon/vte@ Bradford BJbIns Aug. 31, 1943. B. B. HOLMES OXYGEN REGULATOR Filed Dec. 26, 1940 4 Sheets-Sheet 4 mesas Aus. 314, 1943 S PATENT oFFlcE OXYGEN REGULATOR Bradford B.

v`Bendix Aviation Holmes, New York, N.

Corporation, Bendix, N. Acorporation of Delaware Y., asslgnor to J., a

'Application December 26, 1940, serial No. 311,840 a calms. (c1. 12s-142) This invention relates to Loxygen regulators generally, and more particularly tov oxygen regulators of the demand type.

Oxygen regulators of the type heretofore known and used have been designed to supply a-contlnuous flow of oxygen, which may be increased with altitude either manually or automatically, in accordance with a given specification. 'I'he disadvantages encountered with the use of such regulators are that they fail to take into consideration the individual demand o1' the consumer so that an excessive flow must be provided, whereby approximately two-thirds of the oxygen is wasted. Furthermore, known regulators of the prior art necessitate one or more steps of pressure reductionby some means such as an aneroid valve exposed lto the atmosphere and a bi1-pass valve in the automatic type, or a complicated double gauge in the manual type. Other disadvantages lie in that the oxygen :tlow provided by these regulators is varied due to temperature eiect thereon and the regulator units themselves are complicated, cumbersome, dimcult to calibrate and high in manufacturing cost. An object of the present invention is to overcome the foregoing disadvantages and to provide a novel oxygen regulator'wherein the amount of oxygen supplied to the consumer will be in accordance with his individual demand.

Another object oi' the invention is to provide a novel oxygen supplying means whereby oxygen now does not depend upon some arbitrary alti-l tude scale heretofore relied upon, but is regulated in accordance with the operators individual demand.

A further object of the invention is to provide novel automatic oxygen supplying means whereby the oxygen flow is controlled by the consumers breathing so that he is provided at all times with as much oxygen as he needs or demands in accordance with rate of breathing.

Still another object is to provide a novel automatic oxygen regulator having breath controlled means whereby oxygen flow through the regulator is controlled tive that its functioning is not perceptible to the g operator.

by the consumers breathy ing and the breathcontrolled means is so sensi-` Another object of the invention is to provide a novel oxygenregulator of the type above-mentioned with an adjustable manual control 'attached for use in case of failure of the automatic portion of 'the regulator. Y

Still another object oi' the present invention is to provide novel sealing means in an oxygen regulator of the above type which respond accurately and readily to extremely small pressures acting thereon, whereby a substantially constant flow of oxygen is provided to the consumer at all times.

l A still further object of'the invention is to pro- A vide a novel oxygen regulator with the use oi which there is little or no waste of oxygen.

An additional object of the invention is to provide a novel oxygen regulator of simpliiied design whereby the weight and cost of manufacture thereof is substantially reduced and at the same time the regulator provides maximum reliability.

The above and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein one embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are Vfor the purpose of illustration and description only and are not designed as a denition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein like reference characters refer to lik parts throughout the several views,

Figure 1 is a iront elevation of one form of an oxygen regulator embodying the present invention;

Figure 2is a view, in section, taken substantially along line 2-2 of' Figure l;

Figure 3 is a view, in section, taken substantially along line 3-3 of Figure 1;

Figure 4 is a longitudinal view, in section, taken substantially along lines 4-4 of Figure l;

Figure 5 is a longitudinal view, in section, taken substantially along line 5 5 of Figure 4; and

Figure 6 is an enlarged sectional detail view of the novel suction valve of Figure 3.

Referring now to the drawings for a detailed description of the present invention, and more particularly to Figure 1 thereof, one form of oxygen regulator embodying the invention is shown as comprising a suitable housing I0 for mounting the regulator mechanism therein, having a rear flange plate II suitably apertured as at I2 for receiving means for securing the housing to any desired siipport.

The front of the housing has an opening cov ered by a suitable transparent window I3 held in place bya split ring I4 presenting to view a pressure gauge I5 having a dial provided with scale means in the well known manner, superimposed on which is a pointer I6 for indicatingV the pressure of the oxygen at the source such as a tank (not shown. A plate I1 may be further provided at the front of the housing, either formed integrally therewith or secured thereto by means such as screws l 8. for containing printed instructions thereon as to the manner of use of the oxygen regulator. v v

Mounted within the housing I0 and secured to the base plate thereof by suitable means, is a casting generally 'designated at 28 (Figure 4) which deilnes substantially two oppositely in.- verted cylinders A and B,` one being greater in diameter than the other, the former being provided with an end wall 2| and a side wall 22, the latter having an end wall 23 and a side wall 24 which is common to both cylinders. Cylinder B has secured thereto at its open end vby means such as screws 25, a suitable closure member 26 'and the interior of the cylinder thus formed de;-

nes a reduction chamber whose purpose will presently appear. The side wall 22 at the open end of cylinder A, on the other hand, is suitably machined so as to receive a circular yoke member 21 which has secured thereto in any desired manner by means such as wire or linen thread 28, a slack diaphragm -29 whereby the cylinder A is completely enclosed and thus denes a suction chamber whose purpose will likewise presen tly appear.

Cylinder B is provided at its base end with an extended hollow circular flange 30 (Figure 21) vided within the passage 35 holding a lter 36a and a transverse passage '31 communicates with the latter passage. The opposite end of the member 3| is suitably drilled to denne an internally threaded chamber 38 which has resting a1; the lower end thereof a suitable gasket 39 which supports a passaged valve seat member 48 which may be formed of steel or other suit-- able material. A threaded hollow guide member 4IA screw-threadedly engages within chamber 38 and has its lower end resting upon the outer portion of the valve seat 48. Mounted for slidable movement within the hollow guide member 4I is a plunger 42 having a lug 43 at the end ,thereof which carries through the intermediary of a suitable pin 44 a valve 45 formed of lucite or other suitable material. Valve 45 is mounted loosely upon the lug 43 so as to admit a limited self-aligning pivotal movement of plunger 42. The latter plunger is provided with extending portions 56 at its outer periphery serving as guide members `for the reciprocal movement of plunger 42 within the guide member 4 I The opposite end of plunger 42 has a threaded hollow portion for receiving a bolt 41 therein, the latter having an enlarged head 48 adapted to denne a bearing surface for receiving and transmitting closing force upon the valve 45 to-force it against its seat 48.

The end wall 23 of cylinder B has formed integrally therewith a boss 49 having a passage 50 for supporting a threaded rod 5| carrying an aneroid or evacuated capsule 52 mounted in and exposed to the pressures within the reduction chamber. Boss 49 is further provided with a recessed portion receiving a suitable gasket or packing 53 and a lock nut 5Ia engaging the rod 5I and resting on the packing 53 to provide an airtight seal.

Novel toggle linkage is now provided within the reduction chamber responding to the operation of the aneroid whereby the valve 45 is opened or closed to permit entrance oi.' oxygen from the source to the reduction chamber. The linkage comprises two spaced apart parallel plates 54 and 55 suitably fastened by means such as screws 56 to the supporting member 3|. The free ends of plates 54 and 55 are apertured to receive a transverse connecting rod 51 which pivotally supports a yoke member 58 having arms 59 and 69 (Figure 5).

At its free end, the aneroid 52 supports a rod 6I extending into the reduction chamber and the latter is provided with a groove 82 near its outer end.

The free ends of arms 59 and 68 of yoke member 58 are apertured to receive two pins 63 which engage the groove 62 of aneroid or evacuated capsule rod 6| and connect at their outer ends two arms 64 and 85 of a second yoke member 66 with the arms 59 and 60 of yoke 58. The second yoke 68 is provided with a recessed portion 66a for engaging bolt head 48 and has a pin 61 passing therethrough which pivotally supports the yoke 66 within the plates 54 and 55. Slots 68 formed in the plates mount the pin 61 whereby a drop in pressure within the reduction chamber causes aneroid 52 to move outwardly carrying therewith rod 6I and pivotally moving yoke member 58 outwardly as well as yoke 66 due to the fact that pins 63 engage groove 62 and thus follow movement of rod 6I. Since yoke member 58 moves outwardly in a minor arc, yoke 66 will i be moved Anot only outwardly but upwardly for which purpose the slots 68 permit upward motion of pin 61.

As pin 61 moves upwardlyvwithin slots 68, the yoke member 66 is lifted thereby releasing the pressure on bolt head 48 which normally engages the recess 66a. of yoke 66 as well, as the pin 61 and thereby permits unseating of the valve 45.

Oxygen ilows from the source'by way of passage 35, transverse passage 31, passaged valve seat 48 and about plunger 42 into the reduction chamber. With increased pressure in the chamber the aneroir 52 collapses carrying rod 6I and vyoke members 58 and 66 inwardly and the latter yoke pressure will be maintained within .the reduc-y tion chamber, and this represents substantially an absolute pressure of 15 lbs. per square inch 12 lbs. per square inch with a 100 lb. tank pressure. Without the reduction stagethe suction valve to be presently described, which must shut at 2200 lbs. of oxygen, would be too stiii' to opf erate within eures.

A passage 88 (Figure 2) in supporting member 8| communicates at' oneend with transverse passage 81 and at its other end with a conduit 18 which connects the pressure gauge l with the oxygen source whereby the operator or consumer at alltimes will be informed of the amount of oxygen at the supply source as indicated by pointer I8 on the dial. i

The side wall 22 of cylinder A is suitably recessed to receive a hollow valve supporting member 1| (Figure 3) provided with an annular abutment 1|a havingy a gasket 12 betweenit and a related abutment 18 formed in the recessed portion of wall v22. A cap member 14 is pressed inta the base plate of the housing and by way of a sealing ring 15 contacts the member 1|. An anthe desired limits at low tank pres nular groove 18 formed at the outer periphery of member 1| communicates by way of a passage 11 (Figure 5) formed in a portion of flange 88 of cylinder B Joining wall 22 o1' cylinder A to join cylinder A with the reduction chamber formed by cylinder B.

The lower interior portion of' member 1| is threaded for receiving a threaded valve seat 19 having a narrow cylindrical portion 88, the valve seat being formed of steel or other suitable vmaterial. Asuitable gasket 8|a ail'ords an air seal between the upper portion of the valve seat 19 and the member 1|. The cylindrical portion 88 of the valve seat receives for reciprocal movement therein a plunger 8| which carries at its lower end by suitable means the novel valve 82.

As shown in Figure 6, valve 82 consists of a disc member 83 formed oi lucite or other suitable'material and supports a smaller disc member 84 thereon which cooperates with the valve seat and isformed of a substance such as neoprene. Valve 82 is designed to respond to suction equivalent to less than 1,/1 inch of water pressure whereby oxygen will ilow therethrough. Neoprene has been chosen for the above purpose because it is a relatively soft substance, not aifected by the oxygen, and at all times provides a dependable cloi sure free from brittleness and therefore provides longer wear than heretofore afforded by the art.

The free end of plunger 8| carrier nuts 85 thereon and these are normally spaced apart from the edge of the cylindrical portion 88 of the valve seat by means of a coiled spring 88 interposed between the nuts and the valve seat, the latter spring urging valve 82 upwardly against its seat to close communication between chambers A and B. When suction is applied to chamber A, diaphragm 29 acts through a linkage, to be described, to depress plunger 8| and valve 82 from its seat against the action of the spring. Upon building up of pressure in the suction chamber A, diaphragm 28 moves in an opposite direction relieving the force upon plunger 8| and the latter is urged upwardly by way of spring 88`and the valve82 engages its seat bythe additional action ofthe pressure acting on the underside thereof.

The linkage actuated by the diaphragm 29 for operating the valve 82 comprises a pair of parallel spaced apart plates 81 and 88 (Figure 5), secured at their lower ends by suitable means to the supporting member 1| and having slotted y 2,828,914 with a 2200 mengen tank pressure and about' lil) ' Portions 81a andl 88a at their free ends for reciprocally receiving a pin 88 passing through arms 88 and`8| of a primary yoke member 92 and v pivotally mounting a yoke 88 having arms 84 and adjacent the driving rod 98 carried by the diaphragm. Rod 88 passes through the diaphragm 29 and the latter has a portion thereof interposed between two discs 81. (Figure 4) which are clamped together by way of nuts 88 on rod 88.

Rod 98 is provided with a stop pin 88 at the free end thereof (Figure 3) for a purpose to appear later, and a second pin 89 which at its free ends passes through arms 84 and 85 of yoke 83, arms |8| and |82 of a yoke I88`mounted for pivotal movement'about a pin |84, and arms 88 and 9| of primary yoke 82. T'he arms 88 and 8| of yoke 82 are provided with slots |85 and |88 adjacent their connecting Icross member whereby during an outward movement of diaphragm 28, rod 88 is driven outwardly carrying therewith pin V98 which pivots yoke |83 about pfn |84, the latter passing through slots |85 and |88 and being journalled in side plates 81 and 88. Yoke |83, therefore, travels through a minor arc and since it is mounted about a stationary pivot, yoke 93 must move about pin 88 both outwardly and downwardly thereby causing arms 88 and 9| of yoke 82 to move downwardly whereby the-yoke crosspiece engages nut 85 and the plunger 8| to unseat valve 82 thereby causing oxygen flow from chamber B to chamber A'by way of passages 11, 18, chamber |81 and passages |88 and |88 carried by valve seat 19. As soon as oxygen enters chamber A, diaphragm 28 is ymoved in an opposite direction to lift primary yoke 92 causing valve 82 to close due to the action of the oxygen pressure on the'valve disc and the spring 86. As diaphragm 29 moves in its opposite direction and carries'rod 96 therewith, stop pin 88 eventually engages arms 98 and 9| of primary yoke 82 whereby the yokes 93 and |83 are prevented from movingv in an opposite direction and again unseating valve 82 during the later movement of the diaphragm. Pin |88 therefore 'serves a precautionary purpose in permitting valve 82 to be unseated only during a suction on diaphragm 29 and prevents valve opening during pressure ac- 'tion on the diaphragm.

A counterweight ||8 mounted onarm lil (Figure 5), pivotally mounted for movement about s In operation the consumer adjusts his mouthpiece or mask and as soon as he inhales, suction is applied to the chamber A by way of passage l||8 and the reduction in pressure within the chamber actuates diaphragm 28 to move outwardly thereby unseating valve 82 from its seat causing oxygen in ilow by way of passages 11, 16, chamber |81 and passages |88 and |88 fro-m the reduction chamber B tothe suction chamber A. As oxygen flows from the reduction chamber to the suction chamber, the pressure in chamber B is reduced and aneroid 52 'responds to the decreased pressure and moves outwardly. With this movement, pressure-on plunger 42 is released and the oxygen at the source flows through paslbs. of oxygen pressure.

sages 35, 31 and through the valve seat 40 to lift valve 45.;l Oxygen then flows into the reduction chamberiand assoon as a predetermined amount Vof oxygen is present therein aneroid 52 collapses urging yoke 66 oi' the linkage to move plunger 42 to seat valve' 45.

As-pressure in the suction chamber A is built up diaphragm -29 immediately responds thereto to release the force exerted through the linkage upon yoke 92 and thespring 06 in conjunction with the pressures acting upon the lower end of valve 82 urge v'plunger 8| upwardly to close valve 62 on its seat. v

lThe foregoing action is repeated when the consumer again inhales and depletes the oxygen supply in suction" chamber A.y The reduced pressure causes diaphragm 29 to unseat valve 02 whereby f chambers A and B communicate with each other and oxygen iiows from chamber B to A until sufclent oxygen enters suction chamber A to move diaphragm 29 to close valve 82. `Due to the depleted .supply of oxygen in the reduction chamber B, aneroid 52 actuates valve 45 and oxygen iiows into the chamber from the source building up pressure to move the aneroid to again close the valve 45. With this arrangement the operationof the regulator is such as to be imperceptible to the consumer and is highly economical in that little or no oxygen is wasted by it since at all times it supplies only that amount which the individual consumer demands in his breathing.

Should, for any reason, the suction valve 82 fail -to operate, an emergency valve is provided adapted for manual operation whereby oxygen from the reduction chamber B can communicate dlrectly with'the suction chamber A. The emergency valve comprises a manual lever i I 5 (Figure 2), having a forked end clamped by way of a bolt ||6 about a threaded cylinder ||1 mounted with- -in a recessv H8 in the closure member 26. The

upper portion of the recess H8 is provided with a valve seat ||9 with which cooperates a valve |20 carried by a plungery |2| adjustably mounted by way of a spring |22 within the cylinder ||1. Spring |22 denes a safety feature in that should lever IIS be turned too much, valve 20 will not ybe unduly pressed into valve seat l I9. Were, for

example, the plunger I2| a rigid piece operated directly ythrough lever I I5, the valve I 20 might be destroyed by too great a turn of the lever. Manual operation of lever ||5 unseats valve |20 thereby permitting oxygen ow from the reduction chamber B to chamber A by way of passage |23 in the member v26 (Figure 2) about valve |20 and through a passage |24V (Figure 4). In this manner, even though the valve 82 should have failed, a supply of oxygen will be present in `the suction chamber for the consumer's use and the available amount therein will not 4exceed the amount available in the reduction chamber due to the action of the aneroid 52.

The emergency valve further defines an automatic safety valve for the reduction chamber and of the limits of the invention reference will be had lil) housing and therefore the regulator will be relatively light in weight which of necessity is a predominant factor for use in aircraft.

Although only one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may also be made in the design and arrangement voi! the parts without departing from the spirit and scope of the invention, as the same will now be understood by those skilled in the art. For a definition primarily to the appended claims.

Whatisclaimedis: A 1. A respiratory apparatusl comprising a housing. a casing arranged within said housing and forming a pair of substantially cylindrical members, one of said members defining a pressure reduction chamber and the other of said members denning a breathing chamber, a source of respirant gas Vunder pressure communicating with said reduction chamber, valve means for controlling communication betweenv said reduction chamber and said source,an aneroid mounted within said reduction chamber, a toggle mechanism actuated by said aneroid for opening said valve means when the pressure within said reduction chamber has dropped below a predetermined value and for closing said valve when the pressure attains a predetermined valueA within y said reduction chamber, a passage formed in said casing for communicating said reduction chamber with said breathing chamber, a-second valve means for controlling communication between said passage and said breathing chamber, a resilient wall mounted within said breathing chamber and a second toggle mechanism actuated by said wall upon a reduction of pressure within said breathing chamber for opening said last-named valve means to communicate said breathing chamber with saidreduction chamber.

2. A respiratory apparatus comprising a housing, means mounted within said housing and forming a pair o f inverted cylinders having a common wall, oneof said cylinders defining a pressure reduction chamber and the other of said cylinders deiinng a breathing chamber, a source of respirant gas under pressure 'communicating with said reduction chamber, valve means for controlling communication between said reduction chamber and said source, an aneroid mounted within said reduction chamber, means actuated by said aneroid for opening said valve means when the pressure withinsaid reduction chamber has dropped belowI a predetermined value and for closing said valve means when the pressure attains a predetermined value within vsaid reduction chamber, a passage communicating said breathing chamber with said pressure reduction chamberra second valve means. for controlling communication between said cham--l bers, a resilient wall mounted within said breathing chamber, and means actuated by said resilient wall upon a reduction of pressure within said breathing chamber for opening said last-named valve means to communicate said breathing chamber with said reduction chamber.

3. A respiratory apparatus comprising a housing, a casing arranged within said housing and forming a pair of separate chambers, one of said chambers dening a pressure reduction chamber and the other of said chambers deiining a breathing chamber, a source of respirant gas under pressure communicating with said reduction chamber, valve means for controlling communication between said reduction chamber and said source. an aneroid mounted within said reduction chamber,l a rod secured for reciprocal movement by said aneroid, a pair of parallel spaced apart plates rigidly mounted within said reduction chamber and adjacent said aneroid, a pair of oppositely arranged yoke members pivotally mounted on said Plates and having their free ends engageable by said aneroid rod, one of said yoke members engaging Vsaid valve means and adapted for opening said valve means when said aneroid expands to open communication between said source and said reduction chamber, a passage communicating the breathing chamber with said reduction chamber, valve means for controlling communication between said chambers, a iiexible wall' within said breathing chamber responding to a reduction of pressure within said breathing chamber for opening said last-named valve means to communicate said breathing chamber with said reduction chamber, and a breathing conduit connected to said breathing chamber. v

4. A respiratory apparatus comprising a housing, a casing arranged within said housing and forming a pair of adjacent cylindrical members, one of said members deilning a pressure reduction chamber and the other of said members defining a breathing chamber, a source of respirant gas under pressure communicating with said reduction chamber, valve means for controlling communication between said reduction chamber and said source, an aneroid mounted within said reduction chamber, a pair of parallel spaced apart plates mounted within said reduction chamber and adjacent said aneroid, a pair of oppositely arranged yoke members pivotally mounted on said plates and having their free ends movable by said aneroid, one o1' said yoke members normally urging said valve means to a closed position and adapted for releasing said valve means when said aneroid expands to open communication between said source and said reduction chamber, a passage communicating said breathing chamber with said reduction chamber, valve means for controlling communication between said chambers, and a resilient wall within said breathing chamberfor opening said lastnamed valve means to communicate said breathing chamber with said reduction chamber upon a reduction of pressure within said breathing chamber.

5. A respiratory apparatus comprising a housa casing arranged within said housing'4 and forming a pair of separate chambers, one of said ing said valve means toa closed position andl adapted for releasing said valve means when said aneroid expands to open communication between said source and said reduction chamber, a passage communicatingA said breathing chamber with said reduction chamber, valve means for controlling communication between said chambers,

a resilient wall within said breathing chamber responsiveto a reduction of pressure within said breathing chamber, a pair oi' spaced apart parallel plates mounted within said breathing chamber and adjacent said w and means supported by said last-named plates and actuated by said wall, said means including a relatively movable yoke member normally urging said last-named valve means to a closed position and adapted for releasing said last-named valve means to open communication between said chambers, upon a reduction of pressure within said breathing chamber.

6. A respiratory apparatus comprising a housing, a casing arranged within said housing and forming a pair of inverted cylinders having a common wall, one of said lcylinders deilning a pressure reduction chamber and the other oi' said cylinders deiining a breathing chamber, a source of respirant gas under pressure communicating with said reduction chamber, valve means tor controlling communication between said reduction cham-ber and said so-urce, an aneroid mounted within said reduction chamber, a pair of spaced apart parallel plates mounted within said reduction chamber and adjacent said aneroid, a pair of oppositely arranged yoke members pivotally mounted on' said plates and having their free ends movable by said aneroid, one ol said yoke members normally urging said valve means to a closed position and adapted for releasing said valve means when said aneroid expands to open communication between said source and said reduction chambe'r, a passage communicating said breathing chamber with said reduction chamber, valve means for controlling communication between said chambers, a ilexible wall within said breathing chamber responsive to a reduction of pressure within said breathing chamber, a pair of spaced apart parallel plates mounted within said breathing chamber and adjacent saidi'iexible wall, a yoke element slidably supported within said last-named plates and normally urging said last-named valve-means to a closed position, and a pair of yoke members pivotally mounted on said last-named plates and having their free ends movable by said flexible wall whereby said yoke element is actuated to release said last-named valve means to open communication between said chambers upon a reduction in pressure within said breathing chamber.

7. A respiratory apparatus comprising a housing, a casing arranged within said housing and forming' a pair of inverted cylinders having a common wall, one oi' said cylinders dening a pressure reduction chamber and the other o! said cylinders defining a breathing chamber, a source of respirant gas under pressure communicating with said reduction chamber, valve means for controlling communication between said reduction chamber and said source, an aneroid mounted within said reduction chamber, a pair of spaced apart parallel plates mounted within said reduction chamber and adjacent said aneroid, a pair of oppositely arranged yoke members pivotally mounted on said plates` and having their free ends movable by said aneroid, one of said yoke members normally urging said valve means to a closed position and adapted for releasing said valve means when said aneroid expands to open communication between said source and said reduction chamber, a passage communicating said breathing chamber with said pressure "reduction chamber, valve means for controlling communication between said chambers, a resilient-wall within said breathing chamber for opening said last-named valve means to communicate said breathing chamber with said reduction chamber upon a reduction in pressure within said breathing chamber, and an emergency device for bypassing gas from the reduction'chamber to the breathing chamber independently of said lastnamed valve means, said device further acting as a safety valve for releasing Sas from said reduction chamber when the gas therein exceeds a predetermined pressure.

8. A respiratory aparatus comprising a hous lel plates mounted within said reduction chamber and adjacent said aneroid, a pair of oppositeiy arranged yoke members pivotally mounted on said plates and having their tree ends movable by said aneroid. one of said yoke members normally urging said valve means to a closed position and adapted for releasing said valve means when said aneroid expands to open communication between said source and said reduction chamber, a passage communicating said breathing chamber with said reduction chamber. valve means for con-- trolling communication between said chambers comprising a stationary valve seat, a neoprene disc for engaging said seat, a resiliently urged plunger normally urging said disc against said seat. and a resilient wall responding to a reduction of pressure within said breathing chamber for actuating said plunger and unseating said valve disc from said seat to open'communication 20 between said chambers. v BRADFORD B. HOLMES. 

